1. Field of the Invention
The present invention relates to a solid-state imaging apparatus and a driving method thereof.
2. Description of the Related Art
Solid-state imaging apparatuses have come to comprise an increasing number of pixels and provide a higher processing speed in recent years. In an operation mode that uses a large number of pixels and of which a high output rate is required, additions of pixels in column or row direction may be performed. An example of addition in column direction performed in a solid-state imaging apparatus is described in Japanese Patent Application Laid-Open No. 2004-304771 discussed below. An example of combination of added pixels for addition in vertical direction is disclosed in Japanese Patent Application Laid-Open No. 2007-267290. A technique described in Japanese Patent Application Laid-Open No. 2007-267290 suppresses generation of a pseudo signal by adopting such a combination that makes color gravity centers after addition equally spaced.
The way of combining added pixels disclosed in Japanese Patent Application Laid-Open No. 2007-267290 however utilizes only signals from five pixels out of twelve pixel rows, causing loss of pixel signals. As would be obvious, using all pixel signals is the pixel combination that minimizes signal loss. Also, when pixels in every third row are added using an adding operation shown Japanese Patent Application Laid-Open No. 2004-304771, color gravity centers for respective colors are not equally spaced and degradation in image quality caused by a pseudo signal occurs.